What's That Bug? does not endorse extermination

WTB, you guys are wonderfull. I had a question about an Orange Dog a while back @ you guys got back to me right-a-way. Thank-you. I have another Caterpiller I’m curious about. I didn’t see any other pictures of them, so hopefully you’ll get this one I’m sending. (Computer illiterate) I live in Chandler, AZ. ( Phoenix area). Our neighbors have some grape vines growing over our fence. I was very excited that we were going to have fresh grapes until I noticed they were covered by these yellow, black & blue stripped caterpillars. They don’t really seem to be eating the grapes, just the leaves. The plant does seem to be dying however, I don’t know if its from these little guys or just neglect. The one I took a picture of is one of the larger ones. About a 1/2 in. Any-way, what are they? Will they go for any of our other plants, for example, our orange tree? Are they poisonous if eaten by our dogs? Could they be killing the grape vines, & should I be concerned about them? Thanks again,

Hi again Cindy,
We have been away and are just catching up on letters. This caterpillar is a Western Grape Leaf Skeletonizer, Harrisina brillians. This is a new caterpillar for our site. They are a major defoliating pest of grapes and will not spread to your other trees. If they are numerous, they will completly strip a vineyard of leaves. This will not kill the vines, but it will not be a good year for grapes. They will not poison your pets.

What's That Bug? does not endorse extermination

14 Responses to Western Grape Leaf Skeletonizer

  1. jbiggsjr7 says:

    I live in Queen Creek and have vines of my own. While not terribly harmful to your pets those little spines on the caterpillars back will welt you up pretty good if you touch them with anything but your hands.
    I used to pick them off by hand and kill them, but when I would accidently touch one I couldn’t see with the back of my forearm, while reaching in for one I did see, they would cause me to itch and produce big welts on my arm.
    The sale stuff that makes the leaves unsavory to the critters and like the person posted they ony reallly eat the grape leaves so they eventually die becuase they won’t eat the leaves with the chemical on them. Sorry I don’t remember the name of the stuff I bought.

    • bugman says:

      Thanks for your firsthand information. The urticating hair information is a nice warning for our readers.

    • John says:

      Bacillus thuringiensis is the stuff I used. Great for ridding leaves of those suckers. You have to apply at least once a month though because they’ll keep coming back.

  2. Jerry says:

    Those little guys sting and bite make big welds and itch like HECK…

  3. Norma says:

    Does anyone know how to get ride of these guys? I’ve got 3 grape vines. 1 of them is defoliated 100%. The other 2 just started and they are at 20% defoliated, or so. Would anyone know of the best option to annihilate these uninvited guess in my back yard? We just had our first grapes which we were really proud and happy of, but now – I understand the vine without any leaves will no longer produce the fruit till over a year?!

    I would appreciate any input.


  4. dale says:

    I have muscodine grapes,with 1\2 inch brown\black colored worms,stripping the leaves of their greenery,I live in North Florida can you tell me what to use to get rid of the worms.

  5. Shar Haney says:

    How to get rid of the grape leaf skeletonMy grape vine is really looking good , but I notices the little black and yellow bugs just starting to eat my leaves, I need to stop them before they eat my grape vine.

  6. Nancy says:

    1week the little suckers took to eat my leaves off my grapes,I live in Nevada south,more rain this year,maybe could be it…..?…used neem oil,next is Murphy oil soap.

  7. Katherine Oakley says:

    Is there a home remedy for getting rid of the worms that eat the grape leaves

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